<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script>

var num = 123;
var res = String(num);
console.log(res);
console.log(typeof res);

var num = 0;
var res =Boolean(num);
console.log(res);
console.log(typeof res);

var bool=true;
var res=Number(bool);
console.log(res);
console.log(typeof res);

var str='123';
var res=Number(str);
console.log(res);
console.log(typeof res);

var unde = undefined;
var res = Boolean(unde);
console.log(res);
console.log(typeof res);


var unde = undefined;
var res = Number(unde);
console.log(res);
console.log(typeof res);

var unde ;
var res = String(unde);
console.log(res);
console.log(typeof res);

var unde = null;
var res = String(unde);
console.log(res);
console.log(typeof res);

var unde = null;
var res = Number(unde);
console.log(res);
console.log(typeof res);

var str = '';
var res = Number(str);
console.log(res);
console.log(typeof res);
</script>
</body>
</html>